The claimed invention relates generally to disc drive data storage devices and more particularly to a disc drive actuator which uses a Z-axis conductive adhesive film to electrically and mechanically interconnect a head-gimbal assembly (HGA) to a printed circuit board (PCB) actuator arm.
Data storage devices of the type known as xe2x80x9cWinchesterxe2x80x9d disc drives are well known in the industry. Such disc drives magnetically record digital data on circular, concentric data tracks on the surfaces of one or more rigid rotatable storage discs. The discs are axially aligned and mounted on the hub of a spindle motor for rotation at a constant, high speed.
Data are recorded to and retrieved from the discs by an array of vertically aligned read/write head assemblies, or heads, which are controllably positioned adjacent the disc surfaces by an actuator assembly. The actuator assembly typically comprises a rotary voice coil construction so that the actuator assembly rotates about a central pivot axis adjacent the discs through application of current to a coil of a voice coil motor (VCM).
The actuator assembly includes a number of rigid actuator arms which project out over the disc surfaces. Flexible suspension assemblies project from the distal ends of the actuator arms. A head is in turn suspended at the distal end of each suspension assembly. The suspension assemblies operate as springs to bias the heads toward the disc surfaces.
Each head typically includes electromagnetic transducer read and write elements which are carried on an air bearing slider. The slider acts in a cooperative hydrodynamic relationship with a thin layer of air dragged along by the spinning discs to fly each head in a closely spaced relationship to the disc surface. Conductors (such as in a laminated flex circuit) are routed along the suspension assemblies to provide electrical conductive paths for the read and write elements. For reference, the heads, sliders, suspension assemblies and conductors are collectively referred to as head gimbal assemblies, or HGAs.
Most commonly, the flexures are mounted to the actuator arms using mechanical swaging as taught in U.S. Pat. No. 4,829,395 issued to Coon. Mechanical swaging is appropriate where both the actuator arms and the HGAs are made of metallic material, such as aluminum or magnesium. The metal-to-metal contact between the HGAs and the actuator arms obtained through swaging techniques ensures an adequate electrical grounding path between these components.
Certain recent designs for actuators have included actuator arms made from multi-layer printed circuit boards (PCB) instead of a homogenous metal. These designs are advantageous because a number of individual components and the associated electrical interconnects between components can be minimized. However, conventional HGA-arm attachment methodologies such as swaging are not always practical, or even feasible, to implement when the actuator arm has a PCB construction.
In accordance with preferred embodiments, a disc drive is provided with at least one rotatable disc and an actuator assembly adjacent the disc. The actuator assembly includes a rigid printed circuit board (PCB) actuator arm formed of a printed circuit board material, and a flexible head-gimbal assembly (HGA). The HGA preferably comprises a data transducing head, a flexible suspension assembly and a flex circuit including a conductor which is routed along the flexible suspension assembly and connected to the head.
A Z-axis conductive adhesive film is used to electrically and mechanically attach the HGA to a distal end of the PCB actuator arm. The film provides a low resistance electrically conductive path in a first direction across the layer from the HGA to the actuator arm, and at the same time is substantially nonconductive in a second direction normal to the first direction.
In a preferred embodiment, the Z-axis conductive adhesive film is used to affix the flexible suspension assembly to the actuator arm to provide a grounding path to dissipate electrostatic charge in the HGA. In another preferred embodiment, the Z-axis conductive adhesive film is used to affix the flex circuit to the actuator arm to provide a data signal path for the head.
The actuator assembly is preferably formed by steps of providing the PCB actuator arm and the HGA, applying the Z-axis conductive adhesive film to at least a selected one of the PCB actuator arm and the HGA, pressing the HGA onto the PCB actuator arm, and heating the film to establish the desired mechanical and electrical interconnections between the HGA and the PCB actuator arm.
These and various other features as well as advantages that characterize the claimed invention will become apparent upon reading the following detailed description and upon reviewing the associated drawings.